Ambient air control of blower by-passes



Feb. 23, 1954 c. H. SCHOWALTER ET AL 2,669,982

AMBIENT AIR CONTROL OF BLOWER BY-PASSES Filed Sept. 7 1951 2Sheets-Sheet l BLOWER o B To FUEL SUPPLY HEADER 01- ENG/N5 TO ENGINE AIRINTAKE 72 MANIFOLD INVENTORS. C562 fence H fic/aozual 56/ jL azzf/Lew L.firemcz/v GEZJLJ/QAM gz 1954 c. H. SCHOWALTER ET N. 9,

AMBIENT AIR CONTROL OF BLOWER BY-PASSES Filed Sept. 7, 1951 2Sheets-Sheet 2 Clare/2,0611 Schowai'er MaZZ/zew Z. fireman Patented Feb.23, 1954 UNITED STATES PATENT OFFICE AMBIENT AIR ooi f'inot or BLOWERBY-PASSES Clarence H. Schowalter, Beloit, Wis., and Matthew I L.Foreman, Hamilton, Ohio, assignors to Fairbanks, Morse & C0,, Gliicago,Ill.,-'a corporation of Illinois Application September 7, 1951, SerialNo. 245,588

This invention relates to fuel control apparatus for internal combustionengines. More particularly it has to do with apparatus for control- 8Claims (Cl. 123-106) ling the fuel m xture or the fuel-air ratio in en-7 gines arranged to operate on a gaseous fuel.

It has been found that, when operating an engine with a gaseous fuel,particular care must be taken to maintain proper air-fuel ratios inorder to obtain adequate power output under varying load conditions.

It is therefore an important object of the present invention to providea control mechanism for maintaining a desirable air-fuel ratio in anengine under varying load conditions.

Another object of this invention is to provide an air bypass controlsystem which is capable of regulating the air-fuel ratio of an engineand is responsive to the temperature of the ambient air which is drawninto the engine.

Another object is to provide apparatus for regulating the air-fuel ratioin accordance with engine loading and additionally in accordance withthetemperature of the intake air.

The control system of the present invention may be used with anyinternal combustion engine operable on a gaseous fuel. I-Ieretofore thequantity of combustion air delivered to an engine has been controlledmanually or through control units responsive to changes in variousoperating conditions such as the temperature of the exhaust gases, theengine speed, the engine load, the temperature of the fuel, etc. Theapplicants have found that a definite relationship exists between thetemperature of the air and the quantity of air that must be delivered tothe combustion space to obtain eflicient burning of the fuel. Thus ithas been found that an. engine using inlet .air at, for example, 100 F.will require more air for each combustion within each cylinder than itwill if it used inlet air at 75 F. Or, stating this principle in anotherway, the higher the temperature of the air surrounding the'engine, thegreater the quantity of air that must be mixed with a unit charge ofgaseous fuel. The application of this newly discovered relationshipresults in moreefficient operation of the engine since, not only is'thecombustion of the fuel more efiicient, but also "the power reqfiir'edtodrive the blower is kept at a minimum for any set of operatingconditions.

f "According to an important feature of the present" invention, a bypassvalve is installed in the blower tv'liich 'supplies' comb'usti'on airtothe en-" gine. A thermostatic control member" is-mounterl inf theengifi"air"inani'foldw ith a li kage 2 a connecting the movable element of thecontrol member to the bypass valve. The air manifold may receive intakeair from the engine room or from outside the engine room. Hereinafterthis untreated air, which surrounds the eng ne or the engine room, willbe referred to as air at ambient temperature. An increase in the ambientair temperature will directly affect the temperature within the airmanifold thereby causing movement of the temperature responsive elementof the thermostatic control element. Ths movement is transmitted to theblower by the connecting linkage to move the bypass valve to a no bypassposition. Thus, with the control mechanism of this invention, as theambient air temperature rises, more air is directed to the engine sincethe bypass is throttled down. As the ambient air temperature drops, thebypass valve is opened, more air is bypassed, and less air is deliveredto the engine.

A special feature of this invention is the manner in which the operationof the temperaturecontrolled air bypass valve is correlated with theother mechanisms which control the operation of the engine.

On the drawings:

Figure 1 is a schematic drawing of an air bypass controlmechanismconstructed in accordance with the teachings of the presentinvention.

Figure 2 is a schematic drawing of a modified arrangement of the controlmechanismof this invention.

Figure 3 is a schematic drawing of a secon modification of the controlmechanism.

Figure 4 is a schematic drawing of a third valve may be of any'standarddesign adapted to be positioned in a bypass line l3 leading from thedischarge side of a blower back to the suction side and arranged toprogressively open or close' the air passagewaytherethroughi- -A's iswell un derstocd, with such an arrangement the quantity of air deliveredto the engine by the blower will depend upon the angular position of thevalv e it.

Figure 5 illustrates the valve controlled bypass l3 in relation to ablower Blof suitable type, which preferably is driven from the engine(not shown) to be suppliedwitli coinbustion air. cThe engine air supplymanifold M extends from the 55' output sidaof tl'ie-=blowerg whilethe=blower intake servo-motor.

may be supplied with ambient air through the intake conduit I. As shown,the bypass conduit l3 may be connected between the manifold M and theblower intake conduit I.

The angular position of the valve [5 may be changed by means of aconnecting link M which is pivoted at I5 to a radius arm l5 secured tothe shaft l2. According to the present invention the connecting link [4may be adjustably moved by means of a servo-motor l8 that has a plunger20 movable axially inside the servo-motor casing. A short rod 22 isconnected by means of a ball and socket joint 24 to the end of theservo-motor plunger 20. The other end of the rod 22 is pivotallyconnected at 25 to one arm 26a of a bell,- crank 26 that has a fulcrum2'! on a lever 28 and a second arm 26b pivotally connected at 39 to theconnecting link [4.

The servo-motor [8 may be of any suitable type. The one hereinillustrated is similar to that described in Patent No. 2,321,264 and isbriefly described as follows. Oil under pressure is delivered to theinside of a closed cylindrical casing 3| by an oil inlet line 32 andtaken from the casing through a drain line 33. Inside the casing the oilenters the inside of a piston (not shown) through ports which are openedand closed by the rotary movements of a shaft 85. The plunger 20 isconnected to the piston inside the casing so that axial movement of thepiston in response to oil pressure will cause a corresponding shift ofthe plunger 2!] and, through the aforementioned linkage, an angularmovement of the air bypass valve Ill. The extent of plunger movementhere is regulated in accordance with angular settings of the controlshaft 35.

The rotary setting of the shaft 35 is controlled by a speed governor 4!)which is connected, through a suitable linkage 4|, to a rotary shaft 43.An arm 45 is keyed to the shaft 43 and has a free end pivotallyconnected at 46 to a resilient linkage 41. The linkage i! is pivotallyengaged at 48 with an arm 59 that extends outwardly from the shaft 35.It will be recognized therefore that movements of the governor linkage4| will cause a corresponding rotary movement of the shaft 35.

A gas throttle valve 5!, mounted in the engine gaseous fuel supplyconduit 52, is controlled by rotary movement of the shaft 43 through alinkage including an arm 53, a link 54, and a second arm 55 that iskeyed to the shaft 43.

The arm 45 in addition to its relation to shaft 35, may be arranged tocontrol various other engine equipment as for example, in the mannerdescribed in the copending application of the applicant Clarence H.Schowalter, Serial No. 721,549, filed January 11, 1947, now issued asPatent No. 2,612,880. Also, a manual control lever 55 may be providedfor the shaft 43 as shown in said copending application. Further acontrol cam 50a may be arranged to rotate the shaft 53 through an arm501) so that the operation of a master gas shutofi valve (not shown) maybe coordinated with the operation of the gas throttle valve 5!.

It is to be noted here that it may be desired at times, to disablegovernor control of the bypass valve In as effected through theservo-motor 3!. To this end then, the servo-motor may be renderedinoperative as by closing a suitable control valve in the oil pressuredelivery line 32 to the Such valve may be operated directly from thecontrol system (not shown) of the engine.

A special feature of this invention is the proat 55 on a rigid support65.

vision of a temperature responsive member or device 55 which is mountedin an intake air conduit 58 which may be and preferably is a part orsection of the blower intake conduit I (Fig. 5). The member 56 has anelement 51 movable in response to changes in temperature of the air inthe conduit 58. A push rod 59 is mounted on the element 51 and ispivotally connected at 60 to connecting link 5|. The link is pivotallyconnected at 63 to the lever 28 which is fulcrumed Thus, movements ofthe thermosensitive element 51 cause pivoting of the lever 28.

It is to be understood that the plunger 25 of the servomotor 5! willassume a fixed position after it has been adjustably moved in responseto the governor All, and therefore the ball and socket joint 24 willprovide a fixed pivot point in relation to adjusting movements of therod 22 and the bellcrank 26 by the lever 28. In operation, anupward-movement of the connecting link 6| causes counterclockwiserotation of the lever 28 and a movement of the arm 26a and the rod 22toward a straight line position. The pivot 3!! is moved downwardlycausing a rotary adjustment movement of the valve it]. If the connectinglink 6| is moved downwardly, an opposite rotary adjusting movement ofthe valve In is effected.

In Figure 2 a hydraulic system for rotating the air bypass valve isshown. In this modification, the valve Tit (corresponding to valve I0)is mounted on a shaft H which carries an arm 12. A short link T3 ispivotally'connected at one end to the arm 12 and at the other end, to apush rod 15 that carries a piston 11 at one end. The piston is slidablymovable in a closed fluid cylinder #9 that is in turn slidable in afixed cylinder 83. The inner cylinder 19 has a port 82 registering witha port-83 in the outer cylinder 8.0 so that fiuid will pass into thecylinder 19 below the piston 1! from a conduit 85 that is secured at oneend in the port 83. A coil spring 85 is disposed inside the cylinder 19between the piston H and an end wall of the cylinder to resilientlyresist upward movement of the piston H. The fluid conduit 85 isconnected at its other end to a fixed closed fluid cylinder 88 in whicha piston 89 is slidably disposed. A piston rod 9| passes through anopening 82 in the cylinder 88 and is connected, in any suitable manner,to a rod 93 that is carried by a temperature-responsive element 95 of acontrol member or device 95 disposed in an air conduit 9'1. Conduit 91as before, is a part of the blower intake conduit I.

The fluid conduit 85 is maintained in a full condition by a conduit I00which is in flow communication with an oil inlet conduit iUl of aservo-motor I02. A one-way check valve IE3 is connected in the line N25.

Th servo-motor I02 is identical to the servomotor |8 described inconnection with Figure l. A plunger Hi5 projects through the end wall ofthe servo-motor casing and is connected through a bellcrank N15, to arod I07 that is secured to the inner cylinder 19. The bellcrank isfulcrumed at I99 on a fixed support I In. Therefore, movements of theplunger I05 cause corresponding movements of the cylinder 19. It will beunderstood that the servo-motor I02 has a .From the foregoingdescription it .will'be evi--.

d'e'nt that th angularposition of the" air bypass valve may be adjustedeither by theservo motOrIIlZ or by the control member SB, and that eachof'thesecontrol mechanisms operate inde' pendently of each other. i

In Figure 3, a further hydraulic control system for the air bypasscontrol valve is illustrated. In this arrangement a bypass valve 120(againcorresponding to valve I ll) is keyed to a shaft IZI which carriesan arm I22. A connecting link I23 is pivotally connected at one end tothe arm I22, and at the other end, to a piston I25 which is slidablydisposed in an open-ended cylinder I26. One end of the cylinder I26 isclosedby a cap I28 which is provided with an internal passage I30. Abellows I32 is secured in sealed en' gagement between the cap 128 andthe piston I 25 with the passage I in communication'with the inside ofthe bellows. A flexible fluid conduit I34 is connected into the cap I23in flow communication-"with the passage I30; At its'opposite'end theconduit I 312 is connected to a, support housing I35 in communicationwith'a passage I 3'I'pro-; vided-in the top central portion thereof' Aclosed bellows I IIi is disposed" inside the housing I35 having a cappedend MI in sealed engagement with the Wall of the housing. A passage M2in the capped-end communicates the inside of the bellows/I40 with thepassage -I3'I-in the support housing I35. A thermorse'ns'itive controlmember I 43, mounted in an air conduit Hi4, carries a push rod I- whichis secured to the outside of the bellows. Again, conduit I44 representsa partoi the intake conduit I- (Fig; 5) v *Ihe'corfduit' I34 ismaintainedin' a full condition by means of a'fiuidline "M1 connected toan oil inlet line I43 to a servo-motor MB; A check valvelfifi inthe'line' I4! prevents backflow of fluid in'the line. w A rise intemperature of the air in the air conduit l l i'will cause the controlmember I43 to shorten'the length of the bellows l liL 'causing fluidto-be displaced in; the conduit I34 with a resulting-increase in thelength of the bellows I32 and'a movementof the piston I25 against-theresistance off a spring I5I- disposed'i'n' the cylinder' I2I5. Movementof thepiston' I25 causes an angular movement of the valveIZEi in thebypass closing direction. I I 1 The entire cylinder I25 may be bodilymoved by.means of a connecting link I521that is pivotally mounted at'one'nd't'o a tab' I53 projectin from the cap i 26. At the other end thelink I52 is pivetniytonfieaee to abellcrank I55 "which is pivoted ati563 on a' .fixed' support I51. A plunger 453 of the servomotor I49 ispivotally connectedat I68 to the bellcranhj 5 5. Thus axial movements[of the plunger i I59 will caus-. a bodily displacement of the cylinderI26, and, consequeritlyJ anangiilar' movement of "the valve I2ti. Itwill be understood, of course, that thecylinder I2 G is mounted onesuitable'support in a manner whichwill permit bodily movement.

As in the case of the servo-motor I8 of Figure l, a rotary shaft I52 ofthe servo-motor I49 may be controlled by a speed governor or a manualcontrol.

In Figure 4 a still further modification of the air bypass valve controlis illustrated. This arrangement is similar to that illustrated inFigure 3, differing from the latter in that a single closed fluidconduit I65 connects a movable bellows I66 to a thermosensitive bulb I68that is mounted in the air conduit I19. Changes in temperature of theair in a conduit I19 will cause an expansion the conduit I55, whichwillcause a correspondingcontraction or expansion of a bellows I66. Itis to be noted that in this arrangementya gaseous fluid may be'employedin the closed system comprised of -the bellows I56, conduit I'and theremal element I58.

d From the foregoing description it will be seen that there'is providedin this invention a new means for obtaining a more eillcient combustionof the'fuel in an engine. In operation the speed cordance With ambientair temperature changes,"

r'esults in a more eliicient combustion than is possible when theair-fuel ratio is controlled by the-speedg-overnor alone.

In Figure l the close cooperation between the controls imposed by thegovernor and by the thermostatic element --is readily evidentu' On onehand, changes in temperature of the ambient air are effective to shiftthe fulcrum of the se'rvomotor control linkage and thus'regulateitseffectiverange of movement. Conversely, -"a' shiftin the position of thecontrol 1inkage,- due to servo-motor actuation, will shift the'controllink age so that the effective range ofthe -thermo-' static controlelement is changed.

It will be understood that modifications and variations may be effectedWithOllt departing from the scope of the novel concepts of the present''inventionf I We claim:

' 1. In a control system for an engine having'a' combustion chamber, thecombinationof a con duit communicating with the combustion chamber,means for directing intake air'through said conduit, an adjustable valvecontrolling flow'of air through said conduit, a control unit having anelement movable in response to changesin the temperature of the intakeair, a motion trans? mitting mechanism operatively connected betweensaid movable element and said valve to effect adjusting movement of saidvalve in response'to'temperature changes, a governor hav= ing a membermovablein response to changes-in" engine speed, a second conduitarrangedto delivergaseousf-uelto the combustion chamber; a* second adjustablevalve controlling the quantity oeg seous fuel passing through the secondcon'- duit, -a linkage connecting said second valve'with the movableelement of said governor to effectadjusting movement'of said valveinrespon'se ts in. in peed ei meeee eemi t a said-movable element ofsaid governor acne first valve to effect adjusting movement of saidfirst valve in accordance with engine speed, movement of said governorcontrol element being entirely independent of adjusting movement of saidtemperature responsive element.

2. In a system for supplying air to the combustion chamber of an engine,the combination of a conduit communicating with the combustion chamber,a blower having a suction connection to a source of intake air atambient temperature and a discharge connection to said conduit, a bypassconduit connecting the suction side of the blower to the discharge sidethereof, an adjustable valve in said bypass conduit controlling the flowof air therethrough, a closed hydraulic system, a cylinder at each endof said hydraulic system, a first piston slidably disposed in one ofsaid cylinders, a control unit having an element movable in response tochanges in temperature of the intake air at its source and beingconnected to said first piston, and a second piston disposed in theother of said cylinders and connected to said valve to control theair-throttling position thereof, movement of said first piston inresponse to movement of the temperature-responsive element of saidcontrol unit being effective through said hydraulic system to cause acorresponding movement of said second piston and a change in theposition of said valve.

3. In a system for supplying air to the combustion chamber of an engine,the combination of a conduit communicating with the combustion chamber,a blower having a suction connection to a source of intake air atambient temperature and a discharge connection to said conduit, a bypassconduit connecting the discharge side of said blower to the suction sidethereof, an ad'- justable valve in said bypass conduit for restrictingflow of air therethrough, a control unit having an element movable inresponse to changes in the temperature of the intake air, a closedhydraulic line, and a bellows at each end of said line, each bellowshaving a portion mounted in fixed position and a member movable as thebellows expands or contracts, the movable member of one of said bellowsbeing attached to the temperature-responsive member of said controlunit, and the movable member of the other bellows being connected tosaid valve, whereby movements of said temperature-responsive member dueto changes in intake air temperature will cause a corresponding movementof said valve.

4. In a system for supplying air to the combustion chamber of an engine,the combination of a conduit communicating with the combustion chamber,a blower having a suction connection to a source of intake air atambient temperature and a discharge connection to said conduit, a bypassconduit connecting the discharge side of the blower to the suction sidethereof, an adjustable valve in said bypass conduit movable to regulatethe quantity of air bypassed, a control unit having an element movablein response to changes in the temperature of the intake air at itssource, a closed hydraulic system, a first displaceable member in saidhydraulic system connected to the movable element of said control unit,and a second displaceable member in said hydraulic system connected tosaid valve, movement of said control element being effective throughsaid hydraulic system to cause a corresponding movement of said seconddisplaceable member and angular Shifting of said valve.

5. In a system for supplying air to the combustion chamber of an engine,the combination 8: of a conduit communicating with the combustionchamber, a blower having a suction connection to a source of intake airand a discharge connection to said conduit, a bypass conduit connectingthe discharge side of the blower to the suction side thereof, anadjustable valve in said bypass conduit movable to regulate the quantityof air bypassed, a closed fluid system, a hollow thermo-sensitive bulbin said'system in intimate contact with the intake air, changes in thetemperature of the air causing contraction or expansion of the fluid insaid system, a follower member in said system connected to saidadjustable valve and movable in response to expansion or contraction ofthe fluid, to effect adjusting, movements of said valve;

6. In an air supply system for an internal combustion engine, means fordelivering air tothe engine, means for regulating the quantity of airdelivered by the first said means, an engine speed responsiveservo-motor for actuating said regulating means, an operating connectionbetween said regulating means and servo-motor, and air temperatureresponsive means operable independently of said servo-motor, to actuatesaid regulating means.

7. In an air supply system for an internal combustion engine, means fordelivering air to the engine, means for regulating the'quantity of airdelivered to the engine by the first said means, engine speed responsiveservo-motor for actuating said regulating means, an operatingconnectionbetween said regulating means and servomotor, and air temperatureresponsive means operable through said operating connectionandindependently of said servo-motor, to actuate said regulating means. e

8. In an air supply system for an internal combustion engine, means fordelivering air to the engine, means for regulating the quantity ofair-delivered by-the first said means, an engine speed responsiveservo-motor for actuating said regulating means, motion transmittingmeans connected with said regulating means and including an operatingconnection between said regulating means and servo-motor, and airtemperature responsive means operable through said motion transmittingmeans andindependently of said servo-motor to actuate said regulating,

means.

CLARENCE H. SCHO LTER. MATTHEW'L. FOREMAN.

References Cited in the'file of this patent UNITED STATES PATENTS NumberName Date 1,821,662 Muller Sept, 1, 1931 1,838,408 King et a1; Dec. 29,1931 2,088,954 Gregg Aug. 3, 1937 2,388,669 Baker Nov. 13, 19452,504,243 Anderson Apr. 18,1950 2,558,884 Steven et al. July 3, 1951

